Metal oxide films for solar energy control are known. U.S. Pat. No. 3,185,586 to Saunders et al discloses coating glass sheets by applying a suitable organic metal compound in a suitable organic vehicle onto a heated glass surface. Particular films comprising the oxides of cobalt, nickel and tin or iron are preferred. Such films typically have an infinite resistivity (greater than 10.sup.6 ohms per square).
In U.S. Pat. No. 3,850,665, Plumat et al, disclose a metal oxide coating formed on a substrate by applying a composition comprising an acetyl acetonate coprecipitate of two or more metals. The coating is a mixed metal oxide in which the elements are in stoichiometric proportions forming a true molecule of definite composition.